Richard Foster, the actuary for the Centers for Medicare and Medicaid, told Senate Republicans that the overhaul will result in “less generous benefit packages” for Medicare Advantage plans next year.

Democrats have long contended that Medicare Advantage plans – private insurance alternatives to Medicare – overpay private insurers, increasing premiums for everyone, and needs to be reformulated.

But Republicans say dramatic changes to the program mean some seniors won’t be able to keep their plans – a promise President Barack Obama made during the reform debate – and the GOP has made the issue part of its attempt to roll back the health law.